Pass ArrayList from fragment to another fragment(e

Question

I have tried using Static variable for the ArrayList but in the ListFragment class, while debugging it's value is null.

I think the ListFragment gets created before initialising the ArrayList, thats why it's null, but not sure.

Suggest if i can use any other way to send the inflated ArrayList from Fragment class to other Fragment class which extends ListFragment.

Thanks in advance.

Objective (This is the clue, what needs to be done)

In the Monday_fragment's onStart() method use the findByView() method to find the label for the save entry button in the pages view. Using the reference to the button attach a setOnClickListener() method to the save button. You will need to save the time and the diary entry strings contained in the EditText fields on the page in this method.

Use findViewById() to also get a reference to the first EditText field and use this to get the text of the field as a string and save it to a string. Repeat this for the next EditText - the diary entry. You will need a publicly accessible variable to store a reference for the day (Monday..Friday), the date time string, and the diary entry string. Create a new class (diaryLogs) with these fields to hold the values and a single constructor that takes an int (0 Mon, 1 Tue, 2 Wed etc) and two strings for the date time and diary entry to initialise an instance of the object. As a number of entries will be made for the same day, use an ArrayList < diaryLogs > to store the values. As this value will be shared between fragments declare the variable as static in the MainActivity class. Use the .add() method of ArrayList to add the new diaryLog to the ArrayList in your setOnClickListener() method. Repeat this operation for the other diary page fragments.

The monday_list fragment consists of a ListView and a button used to return to the Monday_fragment page. Create these objects in the monday_list xml file. Create a Monday_list_fragment that extends the ListFragment class. In the onCreateView() method inflate() the monday_list resource.

In the onCreate() method you need to provide a single array of strings as the source for the list in the setListAdapter() method used to fill the ListView on the page. The strings are in your static ListArray variable in MainActivity. However, they are not in the form required and you must unpack the diaryLog elements to get to the required strings. To do this you must create a String array big enough to hold the strings to display. As this consistes of a date/time string followed by a diary entry string there will be two such strings for each diaryLog element. Use a Iterator to iterate through your ListArray. Copy the date string and diary string strings into your local string. Then use this local string as the relevant parameter of setListAdapter() so that the ListView displays the required strings.

Add the click handler in the MainActivity java file so that a click on the Save Diary Entries button in the Monday fragment page causes the Monday_list_fragment to be made visible using the FragmentManager. Also add a click handler in MainActivity so that a click on the Return to Monday Diary button returns to the Monday_fragment page.

UPDATE Class MainActivity

public class MainActivity extends Activity {


    public static int Monday=0;
    /*public static int Tuesday=1;
    public static int Wednesday=2;
    public static int Thursday=3;
    public static int Friday=4;
    public static String timeEntry;
    public static String entryEntered;*/
   // public static ArrayList<String> logs;
    //public static String[] entry;
    //public static String time;
    //public static String text;
    //public static String totalEntry;
    //public static ArrayList<DiaryLogs> diaryLogs;
    //public static ArrayList<DiaryLogs> test;
    //public static DiaryLogs[] entryLogs;
    //public static ArrayAdapter<DiaryLogs> monAdapter;
    //public static ArrayList< String > myStringList;
  //public static ArrayList<DiaryLogs> entryLogs;


    public static ArrayList<String> myStringList;

    public static ArrayList<String> getMyStringList() {
        return myStringList;
    }




    public void setMyStringList(ArrayList<String> myStringList) {
        this.myStringList = myStringList;
    }




    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Home_fragment hf = new Home_fragment();
        fragmentTransaction.replace(android.R.id.content, hf);
        fragmentTransaction.commit();
        setContentView(R.layout.activity_main);



        }




    public void monClick(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Monday_fragment mf = new Monday_fragment();
        fragmentTransaction.replace(android.R.id.content, mf);
        fragmentTransaction.commit();
    }

    public void tuesClick(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Tuesday_fragment tf = new Tuesday_fragment();
        fragmentTransaction.replace(android.R.id.content, tf);
        fragmentTransaction.commit();
    }

    public void wedClick(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Wednesday_fragment wf = new Wednesday_fragment();
        fragmentTransaction.replace(android.R.id.content, wf);
        fragmentTransaction.commit();
    }

    public void thursClick(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Thursday_fragment thf = new Thursday_fragment();
        fragmentTransaction.replace(android.R.id.content, thf);
        fragmentTransaction.commit();
    }

    public void friClick(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Friday_fragment ff = new Friday_fragment();
        fragmentTransaction.replace(android.R.id.content, ff);
        fragmentTransaction.commit();
    }

    public void next_Home_Click(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Monday_fragment mf = new Monday_fragment();
        fragmentTransaction.replace(android.R.id.content, mf);
        fragmentTransaction.commit();
    }

    public void previous_Home_Click(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Friday_fragment ff = new Friday_fragment();
        fragmentTransaction.replace(android.R.id.content, ff);
        fragmentTransaction.commit();
    }

    public void next_Mon_Click(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Tuesday_fragment tf = new Tuesday_fragment();
        fragmentTransaction.replace(android.R.id.content, tf);
        fragmentTransaction.commit();
    }

    public void previous_Mon_Click(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Friday_fragment ff = new Friday_fragment();
        fragmentTransaction.replace(android.R.id.content, ff);
        fragmentTransaction.commit();

    }

    public void next_Tues_Click(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Wednesday_fragment wf = new Wednesday_fragment();
        fragmentTransaction.replace(android.R.id.content, wf);
        fragmentTransaction.commit();
    }

    public void previous_Tues_Click(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Monday_fragment mf = new Monday_fragment();
        fragmentTransaction.replace(android.R.id.content, mf);
        fragmentTransaction.commit();

    }

    public void next_Wed_Click(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Thursday_fragment thf = new Thursday_fragment();
        fragmentTransaction.replace(android.R.id.content, thf);
        fragmentTransaction.commit();
    }

    public void previous_Wed_Click(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Tuesday_fragment tf = new Tuesday_fragment();
        fragmentTransaction.replace(android.R.id.content, tf);
        fragmentTransaction.commit();

    }

    public void next_Thurs_Click(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Friday_fragment ff = new Friday_fragment();
        fragmentTransaction.replace(android.R.id.content, ff);
        fragmentTransaction.commit();
    }

    public void previous_Thurs_Click(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Wednesday_fragment wf = new Wednesday_fragment();
        fragmentTransaction.replace(android.R.id.content, wf);
        fragmentTransaction.commit();

    }

    public void next_Fri_Click(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Monday_fragment ff = new Monday_fragment();
        fragmentTransaction.replace(android.R.id.content, ff);
        fragmentTransaction.commit();
    }

    public void previous_Fri_Click(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Thursday_fragment wf = new Thursday_fragment();
        fragmentTransaction.replace(android.R.id.content, wf);
        fragmentTransaction.commit();

    }

    public void home_Click(View view) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        Home_fragment hf = new Home_fragment();
        fragmentTransaction.replace(android.R.id.content, hf);
        fragmentTransaction.commit();

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;

    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // TODO Auto-generated method stub
        switch (item.getItemId()) {
        case R.id.action_profile:
            FragmentManager fragmentManager = getFragmentManager();
            FragmentTransaction fragmentTransaction = fragmentManager
                    .beginTransaction();
            Profile_fragment pf = new Profile_fragment();
            fragmentTransaction.replace(android.R.id.content, pf);
            fragmentTransaction.commit();

            break;
        case R.id.action_saveEntries:

            break;
        case R.id.action_sendAllEntries:
            //call delete dialog
            deleteDialog();
            break;
        }
        return false;
    }

    @Override
    public void onBackPressed() {
        new AlertDialog.Builder(this).setIcon(R.drawable.ic_launcher)
                .setTitle("Save entries to DB first?")
                .setNegativeButton("No", new OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub
                        // if no, close app
                        MainActivity.this.finish();

                    }
                })
                .setPositiveButton(android.R.string.ok, new OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub
                        // if ok, save entries to Database

                    }
                })

                .create().show();

    }

    public void deleteDialog() {

        new AlertDialog.Builder(this).setIcon(R.drawable.ic_launcher)
                .setTitle("Are you sure? This will delete all entries.")
                .setNegativeButton(android.R.string.cancel, new OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub


                    }
                })
                .setPositiveButton(android.R.string.ok, new OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub


                    }
                })

                .create().show();

    }

}

Custom Object Class DiaryLogs

public class DiaryLogs {

    //public static ArrayList<DiaryLogs> entryLogs;

    String timeEntry, entryEntered;
    int day;

    // single constructor that takes an integer and two string
    public DiaryLogs(int day, String timeEntry, String entryEntered) {
        super();
        this.day = day;
        this.timeEntry = timeEntry;
        this.entryEntered = entryEntered;

    }

    public String getTimeEntry() {
        return timeEntry;
    }

    public void setTimeEntry(String timeEntry) {
        this.timeEntry = timeEntry;
    }

    public String getEntryEntered() {
        return entryEntered;
    }

    public void setEntryEntered(String entryEntered) {
        this.entryEntered = entryEntered;
    }

    public int getDay() {
        return day;
    }

    public void setDay(int day) {
        this.day = day;
    }

    @Override
    public String toString() {
        // TODO Auto-generated method stub
        return this.timeEntry + "\n" + this.entryEntered;


    }


}

UPDATE Class Monday_fragment

public class Monday_fragment extends Fragment {

    //public ArrayList<String> myStringList;
    Bundle bundle;
    ArrayList<DiaryLogs> entryLogs;
    EditText timeText;
    EditText entryText;
    DiaryLogs dl;
    String timeEntry;
    String entryEntered;
    ArrayList<String> myStringList;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {

        return inflater.inflate(R.layout.monday_fragment, container, false);

    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        currentDateTime();
        super.onViewCreated(view, savedInstanceState);

    }

    public void currentDateTime() {
        EditText timeText = (EditText) getView().findViewById(
                R.id.dateTimeEText);
        SimpleDateFormat df = new SimpleDateFormat("d/M/yyyy:H:m");
        String dateTime = df.format(Calendar.getInstance().getTime());
        timeText.setText(dateTime);
    }

    /*public ArrayList<String> toStringList(Collection<DiaryLogs> entryLogs) {
        ArrayList<String> stringList = new ArrayList<String>();

        for (DiaryLogs myobj : entryLogs) {
            stringList.add(myobj.toString());
        }

        return stringList;
    }*/
    public ArrayList<String> toStringList(Collection<DiaryLogs> entryLogs) {
        ArrayList<String> stringList =  MainActivity.getMyStringList();

        for (DiaryLogs myobj : entryLogs) {
            String objctString = myobj.toString();

            stringList.add(objctString);
        }
        ((MainActivity)getActivity()).setMyStringList(stringList); 
        return stringList;
    }

    @Override
    public void onStart() {
        entryLogs = new ArrayList<DiaryLogs>();

        timeText = (EditText) getView().findViewById(R.id.dateTimeEText);

        entryText = (EditText) getView().findViewById(R.id.diaryEntryEText);

        Button saveBtn = (Button) getView()
                .findViewById(R.id.saveDiaryEntryBtn);
        saveBtn.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                timeEntry = timeText.getText().toString();

                entryEntered = entryText.getText().toString();

                dl = new DiaryLogs(1, timeEntry, entryEntered);

                entryLogs.add(dl);

                //convert entryLogs to string array list
                //myStringList = toStringList(entryLogs);
                myStringList= MainActivity.getMyStringList();
                myStringList = toStringList(entryLogs);
                //myStringList.addAll(toStringList(entryLogs));

                Toast.makeText(getActivity(), "Entry added \n" + dl,
                        Toast.LENGTH_SHORT).show();
                        entryText.setText("");






            }

        }

        );
        System.out.println(entryLogs);

        Button showBtn = (Button) getView().findViewById(
                R.id.showDiaryEntriesBtn);
        showBtn.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                if (myStringList != null) {
                    bundle = new Bundle();
                    FragmentManager fragmentManager = getFragmentManager();
                    FragmentTransaction fragmentTransaction = fragmentManager
                            .beginTransaction();
                    Monday_list_fragment mlf = new Monday_list_fragment();

                    bundle.putStringArrayList("list", myStringList);
                    mlf.setArguments(bundle);

                    fragmentTransaction.replace(android.R.id.content, mlf);
                    fragmentTransaction.commit();
                }
                if (myStringList == null) {
                    Toast.makeText(getActivity(),
                            "No entry have been added yet", Toast.LENGTH_SHORT)
                            .show();
                }
            }
        });

        super.onStart();
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
    }

}

Class Monday_list_fragment

    public class Monday_list_fragment extends ListFragment {
    ArrayList<String> test;
    Bundle bundle;


    @Override
    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        bundle = getArguments();
        System.out.println(bundle);
       //test = bundle.getStringArrayList("list");

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        // TODO Auto-generated method stub

        return inflater
                .inflate(R.layout.monday_list_fragment, container, false);

    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {

        super.onViewCreated(view, savedInstanceState);

       /* ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(),
                android.R.layout.simple_list_item_1, test);
        // once adapter set throws runtime error
        setListAdapter(adapter);*/

    }



}

Answer 1

You can only pass custom object or ArrayList of custom object via Bundle(or Intent) when the object is either Parcelable or Serializable. One more thing if your fragments are in same activity then why you are passing array. you just create getter and setter for list in your Activity and access them like ((Activity)getActivity).getArraylist() in your listFragment. For creating object Parcelable do something like below.

import android.os.Parcel;
import android.os.Parcelable;

public class Address implements Parcelable {

private String name, address, city, state, phone, zip;

@Override
public int describeContents() {
    return 0;
}

/*
        THE ORDER YOU READ OBJECT FROM AND WRITE OBJECTS TO YOUR PARCEL MUST BE THE SAME
 */

@Override
public void writeToParcel(Parcel parcel, int i) {
    parcel.writeString(name);
    parcel.writeString(address);
    parcel.writeString(city);
    parcel.writeString(state);
    parcel.writeString(phone);
    parcel.writeString(zip);
}


public Address(Parcel p){
    name = p.readString();
    address = p.readString();
    city = p.readString();
    state = p.readString();
    phone = p.readString();
    zip = p.readString();
}

// THIS IS ALSO NECESSARY
public static final Creator<Address> CREATOR = new Creator<Address>() {
    @Override
    public Address createFromParcel(Parcel parcel) {
        return new Address(parcel);
    }

    @Override
    public Address[] newArray(int i) {
        return new Address[0];
    }
};
}

Answer 2

I have seen your code for your given link and thats why I am posting a new Ans. One thing if you read your code carefully, you have declared ArrayAdapter<String> in Monday_fragment, so this list initialize every time when you replace this fragment with other. So just create a ArrayAdapter<String> in MainActivity and getter, setter for the same and change your methode ArrayList<String> toStringList(Collection<DiaryLogs> entryLogs) in the Monday_fragment like below

public ArrayList<String> toStringList(Collection<DiaryLogs> entryLogs) {
    ArrayList<String> stringList =  ((MainActivity)getActivity()).getMyStringList();

    for (DiaryLogs myobj : entryLogs) {
        String objctString = myobj.toString();

        stringList.add(objctString);
    }
    ((MainActivity)getActivity()).setMyStringList(stringList); 
    return stringList;
}